Silicone pressure sensitive adhesive composition and methods for the preparation and use thereof

ABSTRACT

A silicone pressure sensitive adhesive composition is curable to form a silicone pressure sensitive adhesive. The silicone pressure sensitive adhesive composition can be coated on a substrate and cured to form a protective film. The protective film can be adhered to an anti-fingerprint coating on display glass, such as cover glass for a smartphone.

CROSS REFERENCE TO RELATED APPLICATIONS

None.

TECHNICAL FIELD

A silicone pressure sensitive adhesive composition can be cured on asubstrate to form a protective film. The protective film is useful inelectronics applications for protection of display glass having ananti-fingerprint coating on its surface (AF glass).

BACKGROUND

Display devices let users access information easily, however, theysuffer from the drawback of accumulating fingerprints and othermaterials that can damage the display or make the display difficult tosee. The use of AF glass has been proposed to address these issues.

Conventional silicone pressure sensitive adhesives may lack sufficientadhesion on AF glass. If an adhesion promoting additive is included inthe silicone pressure sensitive adhesive composition, the resultingsilicone pressure sensitive adhesive may then have adhesion that is toohigh on certain substrates to allow effective processing to fabricatethe display device.

SUMMARY

A silicone pressure sensitive adhesive (Si-PSA) composition and methodfor its preparation are disclosed. The Si-PSA composition is curable toform a Si-PSA suitable for use in protective films for display devices.A protective film comprising the Si-PSA on a surface of a substrate maybe used on AF glass.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial cross section of a protective film 100.

Reference Numerals 100 protective film 101 polymeric substrate 101bsurface of polymeric substrate 101 102 second Si-PSA 102a surface ofsecond Si-PSA 102 102b opposing surface of Si-PSA 102 103anti-fingerprint hard coating 103a surface of anti-fingerprint hardcoating 103 103b opposing surface of anti-fingerprint hard coating 103104 substrate 104a surface of substrate 104 104b opposing surface ofsubstrate 104 105 Si-PSA 105a surface of Si-PSA 105 105b opposingsurface of Si-PSA 105 106 anti-fingerprint coating 106a surface ofanti-fingerprint coating 106 106b opposing surface of anti-fingerprintcoating 106 107 display cover glass 107a surface of display cover glass107

DETAILED DESCRIPTION

The Si-PSA composition comprises: (A) a polydiorganosiloxane gumterminated with an aliphatically unsaturated group, (B) apolyorganosilicate resin free of aliphatically unsaturated groups, (C) ahydrosilylation reaction catalyst, (D) a polyorganohydrogensiloxane, and(E) an anchorage additive. The Si-PSA composition may optionally furthercomprise an additional starting material selected from the groupconsisting of (F) a hydrosilylation reaction inhibitor, (G) a solvent,and a combination of both (F) and (G). The Si-PSA composition may befree of any starting material that may detrimentally affect adhesion todesired substrates. For example, the Si-PSA composition may be free ofaryl-functional siloxanes, fluorinated siloxanes, or both.

Starting Material (A) Polydiorganosiloxane Gum

The Si-PSA composition comprises (A) a polydiorganosiloxane gumterminated with an aliphatically unsaturated group. Thepolydiorganosiloxane gum has Mn≥500,000 g/mol. The polydiorganosiloxanegum may have unit formula (A-1): (R^(M) ₂R^(U)SiO_(1/2))₂(R^(M)₂SiO_(2/2))_(a), where each R^(M) is an independently selectedmonovalent hydrocarbon group of 1 to 30 carbon atoms that is free ofaliphatic unsaturation; each R^(U) is an independently selectedmonovalent aliphatically unsaturated hydrocarbon group of 2 to 30 carbonatoms; and subscript a has a value sufficient to give thepolydiorganosiloxane gum a number average molecular weight≥500,000g/mol, alternatively 500,000 g/mol to 1,000,000 g/mol, and alternatively600,000 g/mol to 800,000 g/mol.

In unit formula (A-1), each R^(M) is an independently selectedmonovalent hydrocarbon group of 1 to 30 carbon atoms that is free ofaliphatic unsaturation. Alternatively, each R^(M) may have 1 to 12carbon atoms, and alternatively 1 to 6 carbon atoms. Suitable monovalenthydrocarbon groups for R^(M) are exemplified by alkyl groups andaromatic groups such as aryl groups and aralkyl groups. “Alkyl” means acyclic, branched, or unbranched, saturated monovalent hydrocarbon group.Alkyl is exemplified by, but not limited to, methyl, ethyl, propyl(e.g., iso-propyl and/or n-propyl), butyl (e.g., isobutyl, n-butyl,tert-butyl, and/or sec-butyl), pentyl (e.g., isopentyl, neopentyl,and/or tert-pentyl), hexyl, heptyl, octyl, nonyl, and decyl, andbranched alkyl groups of 6 or more carbon atoms; and cyclic alkyl groupssuch as cyclopentyl and cyclohexyl. “Aryl” means a cyclic, fullyunsaturated, hydrocarbon group. Aryl is exemplified by, but not limitedto, cyclopentadienyl, phenyl, anthracenyl, and naphthyl. Monocyclic arylgroups may have 5 to 9 carbon atoms, alternatively 6 to 7 carbon atoms,and alternatively 5 to 6 carbon atoms. Polycyclic aryl groups may have10 to 17 carbon atoms, alternatively 10 to 14 carbon atoms, andalternatively 12 to 14 carbon atoms. “Aralkyl” means an alkyl grouphaving a pendant and/or terminal aryl group or an aryl group having apendant alkyl group. Exemplary aralkyl groups include tolyl, xylyl,benzyl, phenylethyl, phenyl propyl, and phenyl butyl. Alternatively,each R^(M) may be independently selected from the group consisting ofalkyl and aryl. Alternatively, each R^(M) may be independently selectedfrom methyl and phenyl. Alternatively, each R^(M) may be alkyl.Alternatively, each R^(M) may be methyl.

In unit formula (A-1), each R^(U) is an independently selectedmonovalent aliphatically unsaturated hydrocarbon group of 2 to 30 carbonatoms. Alternatively, each R^(U) may have 2 to 12 carbon atoms, andalternatively 2 to 6 carbon atoms. Suitable monovalent aliphaticallyunsaturated hydrocarbon groups include alkenyl groups and alkynylgroups. “Alkenyl” means a branched or unbranched, monovalent hydrocarbongroup having one or more carbon-carbon double bonds. Suitable alkenylgroups are exemplified by vinyl; allyl; propenyl (e.g., isopropenyl,and/or n-propenyl); and butenyl, pentenyl, hexenyl, and heptenyl,(including branched and linear isomers of 4 to 7 carbon atoms); andcyclohexenyl. “Alkynyl” means a branched or unbranched, monovalenthydrocarbon group having one or more carbon-carbon triple bonds.Suitable alkynyl groups are exemplified by ethynyl, propynyl, andbutynyl (including branched and linear isomers of 2 to 4 carbon atoms).Alternatively, each R^(U) may be alkenyl, such as vinyl, allyl, orhexenyl.

Polydiorganosiloxane gums are known in the art and may be prepared bymethods such as hydrolysis and condensation of the correspondingorganohalosilanes or equilibration of cyclic polydiorganosiloxanes.Examples of suitable polydiorganosiloxane gums for use in the Si-PSAcomposition are exemplified by:

-   i) dimethylvinylsiloxy-terminated polydimethylsiloxane,-   ii) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/methylphenyl)siloxane,-   iii) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/diphenyl)siloxane,-   iv) phenyl,methyl,vinyl-siloxy-terminated polydimethylsiloxane,-   v) dimethylhexenylsiloxy-terminated polydimethylsiloxane,-   vi) dimethylhexenyl-siloxy terminated    poly(dimethylsiloxane/methylphenyl)siloxane,-   vii) dimethylvinylsiloxy-terminated    poly(dimethylsiloxane/diphenyl)siloxane,-   viii) a combination of two or more of i) to vii). Alternatively, the    polydiorganosiloxane gum may be selected from the group consisting    of i) dimethylvinylsiloxy-terminated polydimethylsiloxane, v)    dimethylhexenylsiloxy-terminated polydimethylsiloxane, AND a    combination i) and v).

The amount of polydiorganosiloxane gum in the Si-PSA composition issufficient to provide a weight ratio (B)/(A) (i.e., Resin/Gum ratio)of >1.3 to <2.8. Alternatively, Resin/Gum ratio may be 1.85 to 2.0,alternatively 1.90 to 2.0, and alternatively 1.94 to 1.96.Alternatively, the amount of starting material (A) may be 18% to 50%,based on combined weights of starting materials (A) to (F) (e.g., basedon combined weights of all starting materials in the Si-PSA compositionexcluding solvent). Alternatively, the amount of polydialkylsiloxane inthe Si-PSA composition may be 25% to 35%, and alternatively 29% to 31%,on the same basis.

Starting Material (B) Polyorganosilicate Resin

The Si-PSA composition further comprises starting material (B), apolyorganosilicate resin, which comprises monofunctional units (“M”units) of formula R^(M) ₃SiO_(1/2) and tetrafunctional silicate units(“Q” units) of formula SiO_(4/2), where R^(M) is as described above.Alternatively, at least one-third, alternatively at least two thirds ofthe R^(M) groups are alkyl groups (e.g., methyl groups). Alternatively,the M units may be exemplified by (Me₃SiO_(1/2)) and (Me₂PhSiO_(1/2)).The polyorganosilicate resin is soluble in solvents such as thosedescribed above, exemplified by liquid hydrocarbons, such as benzene,toluene, xylene, and heptane, or in liquid organosilicon compounds suchas low viscosity linear and cyclic polydiorganosiloxanes.

When prepared, the polyorganosilicate resin comprises the M and Q unitsdescribed above, and the polyorganosiloxane further comprises units withsilicon bonded hydroxyl groups and may comprise neopentamer of formulaSi(OSiR^(M) ₃)₄, where R^(M) is as described above, e.g., theneopentamer may be tetrakis(trimethylsiloxy)silane. ²⁹Si NMRspectroscopy may be used to measure hydroxyl content and molar ratio ofM and Q units, where said ratio is expressed as {M(resin)}/{Q(resin)},excluding M and Q units from the neopentamer. M:Q ratio represents themolar ratio of the total number of triorganosiloxy groups (M units) ofthe resinous portion of the polyorganosilicate resin to the total numberof silicate groups (Q units) in the resinous portion. M:Q ratio may be0.5:1 to 1.5:1.

The Mn of the polyorganosilicate resin depends on various factorsincluding the types of hydrocarbon groups represented by R^(M) that arepresent. The Mn of the polyorganosilicate resin refers to the numberaverage molecular weight measured using GPC, when the peak representingthe neopentamer is excluded from the measurement. The Mn of thepolyorganosilicate resin is 2,500 g/mol to 5,000 g/mol, alternatively2,700 g/mol to 4,900 g/mol, and alternatively 2,900 g/mol to 4,700g/mol. A suitable GPC test method for measuring Mn is disclosed in U.S.Pat. No. 9,593,209, Reference Example 1 at col. 31.

U.S. Pat. No. 8,580,073 at col. 3, line 5 to col. 4, line 31, and U.S.Patent Publication 2016/0376482 at paragraphs [0023] to [0026] arehereby incorporated by reference for disclosing MQ resins, which aresuitable polyorganosilicate resins for use in the pressure sensitiveadhesive composition described herein. The polyorganosilicate resin canbe prepared by any suitable method, such as cohydrolysis of thecorresponding silanes or by silica hydrosol capping methods. Thepolyorganosilicate resin may be prepared by silica hydrosol cappingprocesses such as those disclosed in U.S. Pat. No. 2,676,182 to Daudt,et al.; U.S. Pat. No. 4,611,042 to Rivers-Farrell et al.; and U.S. Pat.No. 4,774,310 to Butler, et al. The method of Daudt, et al. describedabove involves reacting a silica hydrosol under acidic conditions with ahydrolyzable triorganosilane such as trimethylchlorosilane, a siloxanesuch as hexamethyldisiloxane, or mixtures thereof, and recovering acopolymer having M-units and Q-units. The resulting copolymers generallycontain from 2 to 5 percent by weight of hydroxyl groups.

The intermediates used to prepare the polyorganosilicate resin may betriorganosilanes and silanes with four hydrolyzable substituents oralkali metal silicates. The triorganosilanes may have formula R^(M)₃SiX¹, where R^(M) is as described above and X¹ represents ahydrolyzable substituent such as halogen, alkoxy, acyloxy, hydroxyl,oximo, or ketoximo; alternatively, halogen, alkoxy or hydroxyl. Silaneswith four hydrolyzable substituents may have formula SiX² ₄, where eachX² is halogen, alkoxy or hydroxyl. Suitable alkali metal silicatesinclude sodium silicate.

The polyorganosilicate resin prepared as described above typicallycontain silicon bonded hydroxyl groups, i.e., of formulae, HOSi_(3/2)and/or HOR^(M) ₂SiO_(1/2.) The polyorganosilicate resin may comprise upto 2% of silicon bonded hydroxyl groups, as measured by FTIRspectroscopy. For certain applications, it may desirable for the amountof silicon bonded hydroxyl groups to be below 0.7%, alternatively below0.3%, alternatively less than 1%, and alternatively 0.3% to 0.8%.Silicon bonded hydroxyl groups formed during preparation of thepolyorganosilicate resin can be converted to trihydrocarbon siloxanegroups or to a different hydrolyzable group by reacting the siliconeresin with a silane, disiloxane, or disilazane containing theappropriate terminal group. Silanes containing hydrolyzable groups maybe added in molar excess of the quantity required to react with thesilicon bonded hydroxyl groups on the polyorganosilicate resin.

Alternatively, the polyorganosilicate resin may further comprises 2% orless, alternatively 0.7% or less, and alternatively 0.3% or less, andalternatively 0.3% to 0.8% of units represented by formula XSiO_(3/2)and/or XR^(M) ₂SiO_(1/2) where R^(M) is as described above, and Xrepresents a hydrolyzable substituent, as described above for X¹. Theconcentration of silanol groups present in the polyorganosiloxane may bedetermined using FTIR spectroscopy.

Alternatively, the polyorganosilicate resin may comprise unit formula(B-1): (R^(M) ₃SiO_(1/2))_(z)(SiO_(4/2))_(o), where R^(M) is asdescribed above and subscript z and o have values such that o>1, andsubscript z>4, and a quantity (o+z) has a value sufficient to give thepolyorganosilicate resin the Mn described above.

The Si-PSA composition comprises starting materials (B) in an amount of50% to 65% based on combined weights of starting materials (A) to (F)(e.g., based on combined weights of all starting materials in the Si-PSAcomposition, excluding solvent). Alternatively, the amount of startingmaterial (B) may be 55% to 65%, alternatively 55% to 61%, andalternatively 58% to 61%, on the same basis.

Starting Material (C) Hydrosilylation Reaction Catalyst

Starting material (C) in the Si-PSA composition is a hydrosilylationreaction catalyst. Hydrosilylation reaction catalysts are known in theart and are commercially available. Hydrosilylation reaction catalystsinclude platinum group metal catalysts. Such hydrosilylation reactioncatalysts can be (C-1) a metal selected from platinum, rhodium,ruthenium, palladium, osmium, and iridium. Alternatively, thehydrosilylation reaction catalyst may be (C-2) a compound of such ametal, for example, chloridotris(triphenylphosphane)rhodium(I)(Wilkinson's Catalyst), a rhodium diphosphine chelate such as[1,2-bis(diphenylphosphino)ethane]dichlorodirhodium or[1,2-bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid(Speier's Catalyst), chloroplatinic acid hexahydrate, platinumdichloride. Alternatively, the hydrosilylation reaction catalyst may be(C-3) a complex of the platinum group metal compound with a lowmolecular weight organopolysiloxane, or (C-4) the platinum group metalcompound microencapsulated in a matrix or coreshell type structure.Complexes of platinum with low molecular weight organopolysiloxanesinclude 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complexes withplatinum (Karstedt's Catalyst). Alternatively, the hydrosilylationcatalyst may comprise (C-5) the complex microencapsulated in a resinmatrix. Exemplary hydrosilylation reaction catalysts are described inU.S. Pat. Nos. 3,159,601; 3,220,972; 3,296,291; 3,419,593; 3,516,946;3,814,730; 3,989,668; 4,784,879; 5,036,117; and 5,175,325; and EP 0 347895 B. Microencapsulated hydrosilylation reaction catalysts and methodsof preparing them are known in the art, as exemplified in U.S. Pat. Nos.4,766,176 and 5,017,654. Hydrosilylation reaction catalysts arecommercially available, for example, SYL-OFF™ 4000 Catalyst and SYL-OFF™2700 are available from Dow Silicones Corporation of Midland, Mich.,USA.

The amount of hydrosilylation reaction catalyst used herein will dependon various factors including the selection of starting materials (D) and(A), and their respective contents of silicon bonded hydrogen atoms(SiH) and aliphatically unsaturated groups, and the content of theplatinum group metal in the catalyst selected, however, the amount ofhydrosilylation reaction catalyst is sufficient to catalyzehydrosilylation reaction of SiH and aliphatically unsaturated groups,alternatively the amount of catalyst is sufficient to provide 1 ppm to6,000 ppm of the platinum group metal based on combined weights ofstarting materials containing silicon bonded hydrogen atoms andaliphatically unsaturated hydrocarbon groups; alternatively 1 ppm to1,000 ppm, and alternatively 1 ppm to 100 ppm, on the same basis.Alternatively, when the hydrosilylation reaction catalyst comprises aplatinum-organosiloxane complex, the amount of hydrosilylation reactioncatalyst may be 0.01% to 5% based on combined weights of startingmaterials (A) to (F), (e.g., combined weights of all starting materialsin the Si-PSA composition, excluding solvent).

Starting Material (D) Polyorganohydrogensiloxane

Starting material (D) in the Si-PSA composition is apolyorganohydrogensiloxane of unit formula (D-1): (R^(M)₃SiO_(1/2))₂(R^(M) ₂SiO_(2/2))_(e)(HR^(M) ₂SiO_(2/2))_(f), where R^(M)is as described above, subscript e≥0, subscript f≥3 and a quantity (e+f)is 4 to 500. Alternatively, the quantity (e+f) is sufficient to providethe polyorganohydrogensiloxane with an SiH content of 0.5% to 2%,alternatively 0.75% to 1.75%, and alternatively 0.76% to 1.6%, based onweight of the polyorganohydrogensiloxane.

Methods of preparing polyorganohydrogensiloxanes, such as hydrolysis andcondensation of organohydridohalosilanes, are well known in the art.Suitable polyorganohydrogensiloxanes are exemplified by:

-   i) trimethylsiloxy-terminated poly(dimethyl/methylhydrogen)siloxane,-   ii) trimethylsiloxy-terminated polymethylhydrogensiloxane,-   iii) a combination of both i) and ii).

Starting materials (A) and (D) are present in amounts sufficient toprovide a molar ratio of silicon bonded hydrogen atoms/silicon bondedaliphatically unsaturated groups of 3.4 to 4.1 (referred to as the SiHNiratio) in the Si-PSA composition. Alternatively, the Si-PSA compositionmay comprise the polyorganohydrogensiloxane at 0.1% to 5% of startingmaterial (D), based on combined weights of starting materials (A) to (F)(e.g., combined weights of all starting materials in the Si-PSAcomposition, excluding solvent). Alternatively, the amount of startingmaterial (D) may be 2.5% to 4%, and alternatively 2.8% to 3.8%, on thesame basis.

Starting Material (E) Anchorage Additive

Starting material (E) is an anchorage additive in the Si-PSAcomposition. Without wishing to be bound by theory, it is thought thatthe anchorage additive will facilitate bonding to a substrate by aSi-PSA prepared by curing the Si-PSA composition described herein.However, the presence of the anchorage additive will not detrimentallyaffect the desired peel adhesion, thereby allowing the Si-PSA to beremoved from an electronic device without damaging the device or leavingsignificant residue.

Suitable anchorage additives include silane coupling agents such asmethyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane,3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,bis(trimethoxysilyl)propane, and bis(trimethoxysilylhexane; and mixturesor reaction mixtures of said silane coupling agents. Alternatively, theanchorage additive may be tetramethoxysilane, tetraethoxysilane,dimethyldimethoxysilane, methylphenyldimethoxysilane,methylphenyldiethoxysilane, phenyltrimethoxysilane,methyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane,allyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropyltriethoxysilane, or 3-methacryloxypropyltrimethoxysilane.

Alternatively, the anchorage additive may be exemplified by a reactionproduct of a vinyl alkoxysilane and an epoxy-functional alkoxysilane; areaction product of a vinyl acetoxysilane and epoxy-functionalalkoxysilane; and a combination (e.g., physical blend and/or a reactionproduct) of a polyorganosiloxane having at least one aliphaticallyunsaturated hydrocarbon group and at least one hydrolyzable group permolecule and an epoxy-functional alkoxysilane (e.g., a combination of ahydroxy-terminated, vinyl functional polydimethylsiloxane withglycidoxypropyltrimethoxysilane). Suitable anchorage additives andmethods for their preparation are disclosed, for example, in U.S. PatentApplication Publication Numbers 2003/0088042, 2004/0254274,2005/0038188, 2012/0328863 at paragraph [0091], and U.S. PatentPublication 2017/0233612 at paragraph [0041]; and EP 0 556 023.

Anchorage additives are commercially available. For example, SYL-OFF™297 and SYL-OFF™ 397 are available from Dow Silicones Corporation ofMidland, Mich., USA. Other exemplary anchorage additives include (E-1)vinyltriacetoxysilane, (E-2) glycidoxypropyltrimethoxysilane, (E-3) acombination of (E-1) and (E-2), and (E-4) a combination of (E-3) and apolydimethylsiloxane terminated with hydroxyl groups, methoxy groups, orterminated with both a hydroxy group and a methoxy group. Thecombinations (E-3) and (E-4) may be physical blends and/or reactionproducts.

The amount of anchorage additive depends on various factors includingthe type of substrate to which the Si-PSA composition will be appliedand whether a primer or other surface treatment will be used beforeapplication of the Si-PSA composition. However, the amount of anchorageadditive may be 0.1% to 5%, alternatively 1% to 5%, alternatively 2% to4%, alternatively 3.25% to 4%, and alternatively 3.3% to 3.5%, based onthe combined weights of starting materials (A) to (F) in the Si-PSAcomposition (e.g., based on combined weights of all starting materialsin the Si-PSA composition, excluding solvent).

(F) Hydrosilylation Reaction Inhibitor

Starting material (F) is a hydrosilylation reaction inhibitor(inhibitor) that may optionally be used for altering rate of reaction ofthe silicon bonded hydrogen atoms and the aliphatically unsaturatedhydrocarbon groups of other starting materials in the Si-PSAcomposition, as compared to reaction rate of the same starting materialsbut with the inhibitor omitted. Inhibitors are exemplified by acetylenicalcohols such as methyl butynol, ethynyl cyclohexanol, dimethyl hexynol,and 3,5-dimethyl-1-hexyn-3-ol, 1-butyn-3-ol, 1-propyn-3-ol,2-methyl-3-butyn-2-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol,3-phenyl-1-butyn-3-ol, 4-ethyl-1-octyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol,and 1-ethynyl-1-cyclohexanol, and a combination thereof;cycloalkenylsiloxanes such as methylvinylcyclosiloxanes exemplified by1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane,1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and acombination thereof; ene-yne compounds such as 3-methyl-3-penten-1-yne,3,5-dimethyl-3-hexen-1-yne, and a combination thereof; triazoles such asbenzotriazole; phosphines; mercaptans; hydrazines; amines, such astetramethyl ethylenediamine, 3-dimethylamino-1-propyne,n-methylpropargylamine, propargylamine, and 1-ethynylcyclohexylamine;dialkyl fumarates such as diethyl fumarate, dialkenyl fumarates such asdiallyl fumarate, dialkoxyalkyl fumarates, maleates such as diallylmaleate and diethyl maleate; nitriles; ethers; carbon monoxide; alkenessuch as cyclo-octadiene, divinyltetramethyldisiloxane; alcohols such asbenzyl alcohol; and a combination thereof.

Alternatively, the inhibitor may be a silylated acetylenic compound.Without wishing to be bound by theory, it is thought that adding asilylated acetylenic compound reduces yellowing of the reaction productprepared from hydrosilylation reaction as compared to a reaction productfrom hydrosilylation of starting materials that do not include asilylated acetylenic compound or that include an organic acetylenicalcohol inhibitor, such as those described above.

The silylated acetylenic compound is exemplified by(3-methyl-1-butyn-3-oxy)trimethylsilane,((1,1-dimethyl-2-propynyl)oxy)trimethylsilane,bis(3-methyl-1-butyn-3-oxy)dimethylsilane,bis(3-methyl-1-butyn-3-oxy)silanemethylvinylsilane,bis((1,1-dimethyl-2-propynyl)oxy)dimethylsilane,methyl(tris(1,1-dimethyl-2-propynyloxy))silane,methyl(tris(3-methyl-1-butyn-3-oxy))silane,(3-methyl-1-butyn-3-oxy)dimethylphenylsilane,(3-methyl-1-butyn-3-oxy)dimethylhexenylsilane,(3-methyl-1-butyn-3-oxy)triethylsilane,bis(3-methyl-1-butyn-3-oxy)methyltrifluoropropylsilane,(3,5-dimethyl-1-hexyn-3-oxy)trimethylsilane,(3-phenyl-1-butyn-3-oxy)diphenylmethylsilane,(3-phenyl-1-butyn-3-oxy)dimethylphenylsilane,(3-phenyl-1-butyn-3-oxy)dimethylvinylsilane,(3-phenyl-1-butyn-3-oxy)dimethylhexenylsilane,(cyclohexyl-1-ethyn-1-oxy)dimethylhexenylsilane,(cyclohexyl-1-ethyn-1-oxy)dimethylvinylsilane,(cyclohexyl-1-ethyn-1-oxy)diphenylmethylsilane,(cyclohexyl-1-ethyn-1-oxy)trimethylsilane, and combinations thereof.Alternatively, the silylated acetylenic compound is exemplified bymethyl(tris(1,1-dimethyl-2-propynyloxy))silane,((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, or a combination thereof.The silylated acetylenic compound useful as the inhibitor herein may beprepared by methods known in the art, for example, U.S. Pat. No.6,677,740 discloses silylating an acetylenic alcohol described above byreacting it with a chlorosilane in the presence of an acid receptor.

The amount of inhibitor added herein will depend on various factorsincluding the desired reaction rate, the particular inhibitor used, andthe selection and amount of starting materials (A) and (D). However,when present, the amount of inhibitor may range from >0% to 5%,alternatively >0% to 1%, alternatively 0.001% to 3%, alternatively 0.01%to 2%, alternatively 0.5% to 1%, alternatively 0.65% to 0.8%, andalternatively 0.65% to 0.70%, based on the combined weights of startingmaterials (A) to (F) in the Si-PSA composition (e.g., based on combinedweights of all starting materials in the Si-PSA composition, excludingsolvent).

(G) Solvent

The Si-PSA composition may further comprise starting material (G), asolvent. The solvent may be an organic solvent such as a hydrocarbon, aketone, an ester acetate, an ether, and/or a cyclic siloxane having anaverage degree of polymerization from 3 to 10. Suitable hydrocarbons forthe solvent can be (G-1) an aromatic hydrocarbon such as benzene,toluene, or xylene; (G-2) an aliphatic hydrocarbon such as hexane,heptane, octane, or iso-paraffin; or (G-3) a combination thereof.Alternatively, the solvent may be a glycol ether such as propyleneglycol methyl ether, dipropylene glycol methyl ether, propylene glycoln-butyl ether. Suitable ketones include acetone, methyl ethyl ketone, ormethyl isobutyl ketone. Suitable ester acetates include ethyl acetate orisobutyl acetate. Suitable ethers include diisopropyl ether or1,4-dioxane. Suitable cyclic siloxanes having a degree of polymerizationfrom 3 to 10, alternatively 3 to 6, include hexamethylcyclotrisiloxane,octamethylcyclotetrasiloxane, and/or decamethylcyclopentasiloxane.Alternatively, the solvent may be selected from the group consisting oftoluene, xylene, heptane, ethyl acetate, and a combination of two ormore thereof.

The amount of solvent will depend on various factors including the typeof solvent selected and the amount and type of other starting materialsselected for the Si-PSA composition. However, the amount of solvent mayrange from 0% to 90%, alternatively 0% to 60%, alternatively 20 to 60%,alternatively 45% to 65%, and alternatively 50% to 60%, based oncombined weights of all starting materials in the Si-PSA composition.The solvent can be added during preparation of the Si-PSA composition,for example, to aid mixing and delivery. All or a portion of the solventmay be added with one or more of the other starting materials. Forexample, the polyorganosilicate resin and/or the catalyst, may bedissolved in a solvent before combination with the other startingmaterials in the Si-PSA composition. All or a portion of the solvent mayoptionally be removed after the Si-PSA composition is prepared.

Method of Making the Si-PSA Composition

The Si-PSA composition can be prepared by a method comprising combiningall starting materials as described above by any convenient means suchas mixing at ambient or elevated temperature. The hydrosilylationreaction inhibitor may be added before the hydrosilylation reactioncatalyst, for example, when the Si-PSA composition will be prepared atelevated temperature and/or the Si-PSA composition will be prepared as aone part composition.

The method may further comprise delivering one or more startingmaterials in a solvent (e.g., the hydrosilylation reaction catalystand/or the polyorganosilicate resin) may be dissolved in a solvent whencombined with one or more of the other starting materials in the Si-PSAcomposition. One skilled in the art would understand that if it isdesired that the resulting Si-PSA composition will be solventless (i.e.,will contain no solvent or may contain trace amounts of residual solventfrom delivery of a starting material), then solvent may be removed aftermixing two or more of the starting materials, and in this embodimentsolvent is not intentionally added to the Si-PSA composition.

Alternatively, the Si-PSA composition may be prepared as a multiple partcomposition, for example, when the Si-PSA composition will be stored fora long period of time before use, e.g., up to 6 hours before coating theSi-PSA composition on a substrate. In the multiple part composition, thehydrosilylation reaction catalyst is stored in a separate part from anystarting material having a silicon bonded hydrogen atom, for example thepolyorganohydrogensiloxane, and the parts are combined shortly beforeuse of the Si-PSA composition.

For example, a multiple part composition may be prepared by combiningstarting materials comprising at least some of the polydiorganosiloxanegum, the polyorganohydrogensiloxane, and optionally one or more otheradditional starting materials described above to form a base part, byany convenient means such as mixing. A curing agent may be prepared bycombining starting materials comprising at least some of thepolydiorganosiloxane gum, the hydrosilylation reaction catalyst, andoptionally one or more other additional starting materials describedabove by any convenient means such as mixing. The starting materials maybe combined at ambient or elevated temperature. The hydrosilylationreaction inhibitor may be included in one or more of the base part, thecuring agent part, or a separate additional part. The anchorage additivemay be added to the base part, or may be added as a separate additionalpart. The polyorganosilicate resin may be added to the base part, thecuring agent part, or a separate additional part. Alternatively, thepolyorganosilicate resin may be added to the base part. The solvent maybe added to the base part. Alternatively, starting materials comprisingthe polyorganosilicate resin and some or all of the solvent may be addedin a separate additional part. When a two part composition is used, theweight ratio of amounts of base part to curing agent part may range from1:1 to 10:1. The Si-PSA composition will cure via hydrosilylationreaction to form a Si-PSA.

The method described above may further comprise one or more additionalsteps. The Si-PSA composition prepared as described above may be used toform an adhesive article, e.g., a Si-PSA (prepared by curing the Si-PSAcomposition described above) on a substrate. The method may, therefore,further comprise comprises applying the Si-PSA composition to asubstrate.

Applying the Si-PSA composition to the substrate can be performed by anyconvenient means. For example, the Si-PSA composition may be appliedonto a substrate by gravure coater, comma coater, offset coater,offset-gravure coater, roller coater, reverse-roller coater, air-knifecoater, or curtain coater.

The substrate can be any material that can withstand the curingconditions (described below) used to cure the pressure sensitiveadhesive composition to form the pressure sensitive adhesive on thesubstrate. For example, any substrate that can withstand heat treatmentat a temperature equal to or greater than 120° C., alternatively 150° C.is suitable. Examples of materials suitable for such substratesincluding polymeric films such as polyimide (PI), polyetheretherketone(PEEK), polyethylene naphthalate (PEN), liquid-crystal polyarylate,polyamideimide (PAI), polyether sulfide (PES), polyethyleneterephthalate (PET), polycarbonate (PC), thermoplastic polyurethane(TPU), polyethylene (PE), or polypropylene (PP). Alternatively, thesubstrate may be glass. The thickness of the substrate is not critical,however, the thickness may be 5 μm to 300 μm, alternatively 50 μm to 250μm, and alternatively 50 μm. Alternatively, the substrate may beselected from the group consisting of PET, TPU, PC, and glass.Alternatively, the substrate may be a polymeric substrate, such as PET.

To improve bonding of the Si-PSA to the substrate, the method forforming the adhesive article may optionally further comprise treatingthe substrate before applying the Si-PSA composition. Treating thesubstrate may be performed by any convenient means, such as applying aprimer, or subjecting the substrate to corona-discharge treatment,etching, or plasma treatment before applying the Si-PSA composition tothe substrate.

An adhesive article such as a film or tape may be prepared by applyingthe Si-PSA composition described above onto the substrate describedabove. When the Si-PSA composition contains a solvent, the method mayfurther comprise removing the all, or a portion, of the solvent beforeand/or during curing. Removing solvent may be performed by anyconvenient means, such as heating at a temperature that vaporizes thesolvent without fully curing the Si-PSA composition, e.g., heating at atemperature of 70° C. to 120° C., alternatively 50° C. to 100° C., andalternatively 70° C. to 80° C. for a time sufficient to remove all or aportion of the solvent (e.g., 30 seconds to 1 hour, alternatively 1minute to 5 minutes).

Curing the Si-PSA composition may be performed by heating at atemperature of 80° C. to 200° C., alternatively 90° C. to 180° C.,alternatively 100° C. to 160° C., and alternatively 110° C. to 150° C.for a time sufficient to cure the Si-PSA composition (e.g., for 30seconds to an hour, alternatively 1 to 5 minutes). If cure speed needsto be increased or the process oven temperatures lowered, the catalystlevel can be increased. This forms a pressure sensitive adhesive on thesubstrate. Curing may be performed by placing the substrate in an oven.The amount of the Si-PSA composition to be applied to the substratedepends on the specific application, however, the amount may besufficient such that after curing thickness of the pressure sensitiveadhesive may be 5 μm to 100 μm, and for protective film the thicknessmay be 5 μm to 50 μm, alternatively 10 μm to 40 μm, and alternatively 15μm to 40 μm.

The method described herein may optionally further comprise applying aremovable release liner to the Si-PSA opposite the substrate, e.g., toprotect the Si-PSA before use of the adhesive article. The release linermay be applied before, during or after curing the Si-PSA composition;alternatively after curing. The adhesive article may be a protectivefilm for use in a display device.

Use in a Protective Film

FIG. 1 shows a partial cross section of a protective film (100)overlying a surface (106 a) of an anti-fingerprint coating (106)overlying a surface (107 a) of a display cover glass (107) such that theopposing surface (106 b) of the anti-fingerprint coating (106) contactsthe surface (107 a) of the cover glass (107). The protective film (100)includes a Si-PSA (105) having a surface (105 a) and an opposing surface(105 b). The opposing surface (105 b) of the Si-PSA (105) adheres to thesurface (106 a) of the AF coating with a peel adhesion of >30 g/in, asmeasured according to Reference Example C, below. The Si-PSA may have athickness of 15 μm to 40 μm. The Si-PSA (105) is carried on a substrate(104) having a surface (104 a) and an opposing surface (104 b). Thesurface (105 a) of the Si-PSA (105) contacts the opposing surface (104b) of the substrate (104). The substrate (104) may be selected from thegroup consisting of PET, TPU, PC, and glass and may have a thickness of50 μm to 250 μm.

The protective film (100) may further comprise an anti-fingerprint hardcoating (103) having a surface (103 a) and an opposing surface (103 b)overlying the substrate (104) such that the opposing surface (103 b) ofthe anti-fingerprint hard coating (103) contacts the surface (104 a) ofthe substrate (104).

The protective film (100) may further comprise a second Si-PSA (102)having a surface (102 a) and an opposing surface (102 b) and a polymericsubstrate (101) having a surface (101 b). The second Si-PSA (102) iscoated on the polymeric substrate (101) such that the surface (102 a) ofthe second Si-PSA (102) contacts the surface (101 b) of the polymericsubstrate (101). The opposing surface (102 b) of the second Si-PSA (102)contacts the surface (103 a) of the anti-fingerprint hard coating (103).The second Si-PSA (102) may have a thickness of 10 μm, and the polymericsubstrate (101) may have a thickness of 50 μm. The second substrate(101) may be PET.

The Si-PSA composition and method described above may be used infabrication of the protective film (100). The Si-PSA composition may beapplied to the opposing surface (104 b) of the substrate (104) and curedto form the Si-PSA (105). Alternatively, the Si-PSA compositiondescribed herein may be applied to the surface (101 b) of the polymericsubstrate (101) and cured to form the second Si-PSA (102). Withoutwishing to be bound by theory, it is thought that the Si-PSA prepared bycuring the Si-PSA composition described above may have adhesion on thesurface (106 a) of the anti-fingerprint coating (106) of >30 g/in andadhesion on stainless steel<800 g/in, as measured by the methoddescribed below in Reference Example C.

EXAMPLES

These examples are intended to illustrate the invention to one skilledin the art and are not to be interpreted as limiting the scope of theinvention set forth in the claims. The materials in Table 1 were used inthese examples.

TABLE 1 Starting Commercial Name or Material Description Source Gum 1bis-dimethylvinylsiloxy-terminated Dow Silicones polydimethylsiloxanewith Mn = Corporation 702,000 g/mol by GPC Gum 2bis-dimethylvinylsiloxy-terminated Dow Siliconespoly(dimethyl/methylvinyl)siloxane Corporation with Mn = 702,000 g/molby GPC Polymer bis-vinyldimethylsiloxy-terminated SILASTIC ™polydimethylsiloxane with vinyl SFD-117 content = 0.22% and Mn = 22,000g/mol by GPC Solvent 78% of polymethylsilicate resin Dow Silicones bornehaving Mn = 4,700 dissolved in Corporation Resin 1 22% of solventmixture (of toluene, xylene, and ethylbenzene) Solvent 70% of methylcapped polymethylsilicate Dow Silicones borne resin having Mn = 2,900g/mol by Corporation Resin 2 GPC dissolved in 30% of a solvent mixture(of toluene, xylene, and ethylbenzene) Solvent 66% of a resin comprisingunits of formulae DOWSIL ™ 6-3444 borne(Me₃SiO_(1/2))(Me₂ViSiO_(1/2))(SiO_(4/2)) Resin 3 having a vinyl contentof 3.7% and Mn = 5,000 g/mol by GPC dissolved in 34% of a solventmixture (of toluene, xylene, and ethylbenzene) Crosslinker 1trimethyl-siloxy terminated SYL-OFF ™poly(dimethyl/methylhydrogen)siloxane SL 7028 with SiH content = 1.6%Crosslinker 2 trimethyl-siloxy terminated DOWSIL ™poly(dimethyl/methylhydrogen)siloxane 6-3570 with SiH content = 0.76%Anchorage mixture of reactive silanes SYL-OFF ™ 397 Additive 1 ETCH1-ethynyl-1-cyclohexanol commercially available from various sources4000 Catalyst Karstedt's Catalyst SYL-OFF ™ 4000 Catalyst Solvent 1Toluene commercially available from various sources

DOWSIL™, SILASTIC™, and SYL-OFF™ products are commercially availableform Dow Silicones Corporation of Midland, Mich., USA.

Reference Example A—Preparation of Si-PSA Compositions

Samples of Si-PSA compositions were prepared by combining the startingmaterials in the amounts (in weight parts) shown below in Table 2.Solvent borne Resins and Gums (and/or Polymer) were first combined.Crosslinkers, anchorage additive, solvent, and catalyst were then added.All the starting materials were mixed at room temperature.

Reference Example B—Preparation of Si-PSA Tape

Each Si-PSA composition prepared as described above in Reference ExampleA was applied on PET film with a thickness of 40 μm to 60 μm and heatedin an oven at 150° C. for 2 minutes. The Si-PSA had a thickness of 25 μmto 35 μm after heating.

The resulting tape samples were applied to substrates such that theSi-PSA contacted the substrate. The substrates were AF glass and SUS,and samples were kept at RT for 30 minutes after contacting the Si-PSAwith the substrate before testing.

Reference Example C—Adhesion Testing

Each tape sample prepared as described above was tested for adhesion tothe AF glass and SUS substrates by peeling each tape from the substrateand checking if there was any Si-PSA transferred onto the substrate fromthe PET film. An Adhesion/Release Tester AR-1500 was used. The width ofeach PET sheet was 1 inch. Peel speed and angle were 0.3 m/min and 180°,respectively. The unit was grams/in. Results are shown below in Table 2.

TABLE 2 Sample Preparation and Test Results Starting Material C2 C10 W1W2 W3 Solvent Borne Resin 1 0 5.62 12.9 0 0 Solvent Borne Resin 2 13.113.1 0 13.1 13.1 Solvent Borne Resin 3 0 0 0 0 0 Gum 1 10.1 0 6.66 6.666.66 Gum 2 0 6.66 0 0 0 Polymer 0 3.3 0 0 0 Crosslinker 1 0.5 0 0.5 0.50.4 Crosslinker 2 0.22 0.44 0.22 0.22 0.22 Anchorage Additive 1 0.750.75 0.75 0.75 0.75 ETCH 0.15 0.15 0.15 0.15 0.15 4000 Catalyst 0.9 0.40.76 0.9 0.4 Solvent 1 26.5 26.4 22.37 26.54 21.37 (B)/(A) (Resin/Gum)1.30 2.80 1.94 1.96 1.96 Ratio SiH/Vi Ratio 4.0 1.2 4.1 4.1 3.4 Adhesionto AF glass 5 10.4 31.2 40.5 44 g/inch Adhesion to SUS g/inch 469 581675 758 675

Problems to be Solved

Conventional silicone pressure sensitive adhesives lack the combinationof properties desired for protective films used on AF glass in displaydevices, such as high adhesion to anti-fingerprint coatings on glass andlow adhesion to stainless steel.

Electronic device fabricators are seeking a new protective film for AFglass. The peel adhesion should be >30 g/in on AF glass and <800 g/in onSUS. Selective adhesion to different substrates is a challenge for theSi-PSA industry. Conventional Si-PSAs may be able to meet one, but notboth, of these peel adhesion criteria.

INDUSTRIAL APPLICABILITY

The working examples above showed that Si-PSA compositions that cure toform Si-PSAs were prepared with peel adhesion measured by the method ofReference Example C of >30 g/in on AF glass and <800 g/in on SUS. Forexample, the working examples W1, W2, and W3 had peel adhesion on AFglass of 31.2 g/inch, 40.5 g/in, and 44 g/in, respectively. Withoutwishing to be bound by theory, it is thought that the Si-PSAcompositions described herein may cure to form Si-PSAs with peeladhesion on AF glass of >30 g/in to 45 g/in, alternatively 40 g/in to 45g/in, and alternatively 31 g/in to 44 g/in. The working examples abovefurther showed that Si-PSA compositions that cure to form Si-PSAs wereprepared with peel adhesion measured by the method of Reference ExampleC of <800 g/in on SUS. For example, working examples W1, W2, and W3 hadpeel adhesion on SUS of 675 g/in, 758 g/in, and 675 g/in, respectively.Without wishing to be bound by theory, it is thought that the Si-PSAcompositions described herein may cure to form Si-PSAs with peeladhesion on SUS of 650 g/in to <760 g/in, alternatively 650 g/in to 700g/in.

The selective adhesion to AF glass and SUS properties of the Si-PSAprepared from the Si-PSA composition described herein make theprotective film suitable for use on 2.5D AF glass and 3D AF glass usedin display devices, such as mobile telephones, mobile televisionreceivers, wireless devices, smartphones, personal data assistants,wireless electronic mail receivers, hand-held or portable computers,netbooks, notebooks, smartbooks, tablets, global positioning systemreceivers/navigators, cameras, digital media players, camcorders, gameconsoles, and electronic reading devices.

DEFINITIONS AND USAGE OF TERMS

All amounts, ratios, and percentages herein are by weight, unlessotherwise indicated. The SUMMARY and ABSTRACT are hereby incorporated byreference. The terms “comprising” or “comprise” are used herein in theirbroadest sense to mean and encompass the notions of “including,”“include,” “consist(ing) essentially of,” and “consist(ing) of. The useof “for example,” “e.g.,” “such as,” and “including” to listillustrative examples does not limit to only the listed examples. Thus,“for example” or “such as” means “for example, but not limited to” or“such as, but not limited to” and encompasses other similar orequivalent examples. The abbreviations used herein have the definitionsin Table 3.

TABLE 3 Abbreviations Abbreviation Definition 2.5D glass refers to glassthat is flat in the middle, but is rounded down at the edges 3D glassrefers to glass that is either curved in the middle, or has an upwardsridge at the edge, either possibly in combination with a rounded downedge (or other more complex curves) AF anti-fingerprint AF glass glasshaving an anti-fingerprint coating on its surface. DP degree ofpolymerization FTIR Fourier Transform Infra Red: The concentration ofsilanol groups present in the polyorganosilicate resin may be determinedusing FTIR spectroscopy according to ASTM Standard E-168-16. g gramsg/in grams per inch g/mol grams per mol GPC gel permeationchromatography kg kilogram m meters Me methyl min minutes mm millimetersMn number average molecular weight measured by GPC as disclosed in U.S.Pat. No. 9,593,209, Reference Example 1 at col. 31 mPa · s megaPascalseconds NMR Nuclear Magnetic Resonance: the 29 Si NMR techniquedescribed in U.S. Pat. No. 9,509,209, Reference Example 2 at col. 32 canbe used to measure molar ratios of M to Q siloxy units in thepolyorganosilicate resin. PET polyethylene terephthalate Ph phenyl PSApressure sensitive adhesive, including but not limited to acrylic,rubber, and/or silicone pressure sensitive adhesives RT room temperatureof 20° C. to 25° C. Si-PSA silicone pressure sensitive adhesive SUSstainless steel μm micrometers Vi vinyl

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation. Withrespect to any Markush groups relied upon herein for describingparticular features or aspects, different, special, and/or unexpectedresults may be obtained from each member of the respective Markush groupindependent from all other Markush members. Each member of a Markushgroup may be relied upon individually and or in combination and providesadequate support for specific embodiments within the scope of theappended claims.

Furthermore, any ranges and subranges relied upon in describing thepresent invention independently and collectively fall within the scopeof the appended claims, and are understood to describe and contemplateall ranges including whole and/or fractional values therein, even ifsuch values are not expressly written herein. One of skill in the artreadily recognizes that the enumerated ranges and subranges sufficientlydescribe and enable various embodiments of the present invention, andsuch ranges and subranges may be further delineated into relevanthalves, thirds, quarters, fifths, and so on. As just one example, arange of “1 to 30” may be further delineated into a lower third, i.e., 1to 10, a middle third, i.e., 11 to 20, and an upper third, i.e., from 21to 30, which individually and collectively are within the scope of theappended claims, and may be relied upon individually and/or collectivelyand provide adequate support for specific embodiments within the scopeof the appended claims. In addition, with respect to the language whichdefines or modifies a range, such as “at least,” “greater than,” “lessthan,” “no more than,” and the like, it is to be understood that suchlanguage includes subranges and/or an upper or lower limit.

1. A silicone pressure sensitive adhesive composition comprising: 18weight % to 50 weight %, based on combined weights of starting materials(A) to (F) of (A) a polydiorganosiloxane gum of unit formula (A-1):(R^(M) ₂R^(U)SiO_(1/2))₂(R^(M) ₂SiO_(2/2))_(a), where each R^(M) is anindependently selected monovalent hydrocarbon group of 1 to 30 carbonatoms that is free of aliphatic unsaturation; each R^(U) is anindependently selected monovalent aliphatically unsaturated hydrocarbongroup of 2 to 30 carbon atoms; and subscript a has a value sufficient togive the polydiorganosiloxane gum a number average molecular weightof >500,000 g/mol; 50 weight % to 65 weight %, based on combined weightsof starting materials (A) to (F) of (B) a polyorganosilicate resincomprising unit formula (B-1): (R^(M) ₃SiO_(1/2))_(z)(SiO_(4/2))_(o),subscripts z and o have values such that z>4, o>1, and a quantity (z+o)has a value sufficient to provide the polyorganosilicate resin with anumber average molecular weight of 2,500 g/mol to 5,000 g/mol; wherestarting materials (A) and (B) are present in a weight ratio of (B)/(A)(Resin/Gum ratio) >1.3 to <2.8 0.01 weight % to 5 weight %, based oncombined weights of starting materials (A) to (F) of (C) ahydrosilylation reaction catalyst 0.1 weight % to 5 weight %, based oncombined weights of starting materials (A) to (F) of (D) apolyorganohydrogensiloxane of unit formula (D-1): (R^(M)₃SiO_(1/2))₂(R^(M) ₂SiO_(2/2))_(e)(HR^(M) ₂SiO_(2/2))_(f), wheresubscript e≥0, subscript f≥3 and a quantity (e+f) is 4 to 500; wherestarting materials (A) and (D) are present in amounts such that molarratio of silicon bonded hydrogen atoms in starting material (D) toaliphatically unsaturated groups in starting material (A) (SiH/Vi ratio)is 3.4 to 4.1; 0.1 weight % to 5 weight %, based on combined weights ofstarting materials (A) to (F) of (E) an anchorage additive; 0 weight %to 5 weight %, based on combined weights of starting materials (A) to(F) of (F) a hydrosilylation reaction inhibitor; and 0 weight % to 60weight %, based on combined weights of all starting materials in thecomposition of (G) a solvent, with the proviso that the siliconepressure sensitive composition is free of fluorinated startingmaterials.
 2. The composition of claim 1, where in starting material(A), the polydiorganosiloxane gum, each R^(M) is an independentlyselected alkyl group of 1 to 10 carbon atoms; each R^(U) is anindependently selected alkenyl group of 2 to 10 carbon atoms; andsubscript a has a value of sufficient to give the polydiorganosiloxanegum a number average molecular weight of 500,000 to 1,000,000 g/mol. 3.The composition of claim 1, where in starting material (B), thepolyorganosilicate resin, each R^(M) is an independently selected alkylgroup of 1 to 10 carbon atoms; and subscripts z and o have values suchthat the quantity (z+o) has a value sufficient to provide thepolyorganosilicate resin with a number average molecular weight of 2,900g/mol to 4,700 g/mol.
 4. The composition of claim 1, where startingmaterial (C), the hydrosilylation reaction catalyst, comprises aplatinum-organosiloxane complex.
 5. The composition of claim 1, where instarting material (D), the polyorganohydrogensiloxane, each R^(M) is anindependently selected alkyl group of 1 to 10 carbon atoms; and thequantity (e+f) has a value sufficient to provide thepolyorganohydrogensiloxane with an SiH content of 0.76 weight % to 1.6weight %.
 6. The composition of claim 1, where each R^(M) is methyl andeach R^(U) is selected from the group consisting of vinyl, allyl, andhexenyl.
 7. The composition of claim 1, where starting material (E), theanchorage additive, is selected from the group consisting of (E-1)vinyltriacetoxysilane, (E-2) glycidoxypropyltrimethoxysilane, (E-3) acombination of (E-1) and (E-2), and (E-4) a combination of (E-3) and apolydimethylsiloxane terminated with hydroxyl groups, methoxy groups, orterminated with both a hydroxy group and a methoxy group.
 8. Thecomposition of claim 1, where starting material (F), the hydrosilylationreaction inhibitor, is present and is selected from the group consistingof (F-1) 1-ethynyl-1-cyclohexanol, (F-2) methyl butynol, (F-3) diallylmaleate, and (F-4) a combination of two or more of (F-1), (F-2) and(F-3).
 9. The composition of claim 1, where (G) the solvent is presentand is selected from the group consisting of toluene, xylene, heptane,ethyl benzene, and a combination of two or more thereof.
 10. A siliconepressure sensitive adhesive prepared by curing the composition ofclaim
 1. 11. A protective film comprising: 1) the silicone pressuresensitive adhesive of claim 10, 2) a first polymeric substrate having afirst surface and an opposing second surface, where the siliconepressure sensitive adhesive is disposed on the first surface.
 12. Amethod for preparing protective film comprising: optionally 1) treatinga surface of a substrate, 2) coating a silicone pressure sensitiveadhesive on the surface of the substrate, where the silicone pressuresensitive adhesive composition comprises: 18 weight % to 50 weight %,based on combined weights of starting materials (A) to (F) of (A) apolydiorganosiloxane gum of unit formula (A-1): (R^(M)₂R^(U)SiO_(1/2))₂(R^(M) ₂SiO_(2/2))_(a), where each R^(M) is anindependently selected monovalent hydrocarbon group of 1 to 30 carbonatoms that is free of aliphatic unsaturation; each R^(U) is anindependently selected monovalent aliphatically unsaturated hydrocarbongroup of 2 to 30 carbon atoms; and subscript a has a value sufficient togive the polydiorganosiloxane gum a number average molecular weightof >500,000 g/mol; 50 weight % to 65 weight %, based on combined weightsof starting materials (A) to (F) of (B) a polyorganosilicate resincomprising unit formula (B-1): (R^(M) ₃SiO_(1/2))_(z)(SiO_(4/2))_(o),subscripts z and o have values such that z>4, o>1, and a quantity (z+o)has a value sufficient to provide the polyorganosilicate resin with anumber average molecular weight of 2,500 g/mol to 5,000 g/mol; wherestarting materials (A) and (B) are present in a weight ratio of (B)/(A)(Resin/Gum ratio) >1.3 to <2.8 0.01 weight % to 5 weight %, based oncombined weights of starting materials (A) to (F) of (C) ahydrosilylation reaction catalyst 0.1 weight % to 5 weight %, based oncombined weights of starting materials (A) to (F) of (D) apolyorganohydrogensiloxane of unit formula (D-1): (R^(M)₃SiO_(1/2))₂(R^(M) ₂SiO_(2/2))_(e)(HR^(M) ₂SiO_(2/2))_(f), wheresubscript e≥0, subscript f≥3 and a quantity (e+f) is 4 to 500; wherestarting materials (A) and (D) are present in amounts such that molarratio of silicon bonded hydrogen atoms in starting material (D) toaliphatically unsaturated groups in starting material (A) (SiH/Vi ratio)is 3.4 to 4.1; 0.1 weight % to 5 weight %, based on combined weights ofstarting materials (A) to (F) of (E) an anchorage additive; 0 weight %to 5 weight %, based on combined weights of starting materials (A) to(F) of (F) a hydrosilylation reaction inhibitor; and 0 weight % to 60weight %, based on combined weights of all starting materials in thecomposition of (G) a solvent, with the proviso that the siliconepressure sensitive composition is free of fluorinated startingmaterials; optionally 3) removing some or all of the solvent, whenpresent, and 4) curing the pressure sensitive adhesive composition. 13.A method comprising preparing a protective film of by the method ofclaim 12, and overlying the protective film on an anti-fingerprintcoating for a display glass.